1. Field of the Invention
The present invention relates to liquid crystal display apparatuses, liquid-crystal-display control methods, and computer programs, and more particularly, to a liquid crystal display apparatus capable of performing a display control operation on a liquid crystal display to improve visibility, a liquid-crystal-display control method, and a computer program.
2. Description of the Related Art
Liquid crystal displays are flat, lightweight displays and consume low power. Because of these advantages, the liquid crystal displays are used in various apparatuses, such as televisions (TVs), personal computers (PCs), and cameras. Since the liquid crystal displays are not luminescent, backlights are used in transmissive liquid crystal displays to illuminate display screens from the back in order to improve the visibility and to be usable even in dark places. Exemplary backlights include fluorescent lamps, light-emitting diodes (LEDs), and the like. With the use of backlights, however, the image quality is deteriorated.
In the related art, for example, Japanese Patent No. 3591213 describes a method of adjusting the brightness without sacrificing the image quality by performing a display control operation on a liquid crystal display and additionally controlling the output intensity of a backlight.
In the case where a fluorescent lamp is used as a backlight, adjustment of luminance is difficult to perform. In the case where an LED is used as a backlight, fine adjustment of brightness involves a high-performance circuit, resulting in an increase in the cost. A general, inexpensive backlight adjustment circuit has difficulty in sufficiently reducing the voltage of an object to be controlled because of transistor saturation. As a result, the lower limit of a backlight brightness adjustable range is set to a relatively high level. An apparatus including such a circuit fails to set the brightness adjustment range to a sufficiently wide range, and it becomes difficult to avoid degradation of the image quality due to the use of the backlight. In particular, the use of the backlight in a dark environment causes an insufficient reduction in the brightness, which may in turn cause deterioration of the visibility.